Mobile electronic devices, such as tablets, e-readers and smart phones, include cameras for image capture. Many devices also include a flash LED for illuminating a subject or scene that is to be imaged when the device is in a dark environment. Satisfactory image quality depends on obtaining a light output from the flash LED that is sufficiently bright and sufficiently uniform in brightness and chromaticity across a field of view of the camera. Accordingly, it is necessary to measure and calibrate light emitted from the flash LED to determine its actual output. Such calibration may be performed at the component (flash LED) level or at the device (tablet, e-reader, phone) level of assembly, or both, during design development, and/or as part of quality control testing of production components and devices. Traditionally, measuring the brightness and uniformity of a strobe flash has been accomplished by imaging, with a film camera, a brightness pattern on a standard gray surface wall illuminated by the strobe flash. Post-processing of the film by trained specialists would assess the brightness level (lux level) of light falling on the wall to make a qualitative assessment of the flatness of the illumination across the field of view may be determined. These known techniques are labor intensive and can be difficult to implement where the illumination source is a flash LED rather than a conventional xenon flash tube because of the comparatively low intensity of an LED flash, as well as more severe temporal and spatial non-uniformities typical of an LED flash.